Commutator for dynamo-electric machines



(No Model.)

2 Sheets-Sheet l. N. TESLA.

GOMMUTATOR FOR DYNAMO ELECTRIC MAGHINESL No.882,845. Patented May 15, 1888 win 8 58: I

:jLQ/AZEWOR,

Arm/m (No Model.) v 2 SheetsSheet 2.

NTESLA. .GOMMUTATOR FOE DYNAMO EI ECTRIG MACHINES. No. 882,845 Patented May 15, 1888.

vH an" in...

I IIVVEIVTOR v ATTORNEYS,

a UNITED. STATES- PATENT OFFICE.

NIKOLrMTESLA, or NEW YORK, N. Y., Assronos or ONE-HALF o CHARLES r. PECK, or ENGLEWOOD, NEW JERSEY.

- COVMMUTATOR FOR uvmuvlo-steernlc MACHINES.

SPECIFICATION-forming part of Letters Patent N 382,815, dated May 1888.

Application filed Apr-i130. 188T.

Seriulh'a'iiltiflll; (No model),

To all whom it may concern:

Be it known that I, NIKOLA TESLA, from Smiljan, Lika, border country of Austria-Hungary,at presentresidingiu the city, county, and

- 5 State of New York, have inventedcertain new and useful I uiprove'mentsin Commutators for Dynamo {Electric Machines and Motors, of which the following is a specification, reference being had to the drawings accompanying to and forming a partof the same.

This invention relates to dynamo-electric machines or motors, and is an improvement in thedevices for commutating and collecting the cnrrents.-,v V r I 'l lhe objects of tlie'inycntion are, first, to avoid the sparking and the gradual wearing away or destruction of the commutator-slog mcntsand brushes or collectors resulting therefrom; second, to obviate the necessity of readjustment of the commutator or'thc brushes or collectors and other consequences "of the wear of the same; third, to render practicablethe construction of very large d ynamo-electric machines and motors with the minimum numberof com initiator-segments, and,fourth,'toincrease the efficiency and safety and reduce the cost of the machine. I

In carrying out my invention in a manner to accomplish these results I construct a cominutator and the collectors therefor in two segments areilush. The part which takes the placcof the usualbrushemor what Iterin the "c'ollcctor, is'a disliof the same character as the connnutatoland having-a surface similarly formed with two insulating and two Inetallic segments. These-two parts are mounted with their faces in contact and in such mannor that the rotation of the armature causes of these segments, .are in electrical connection with the ends of the coils on the armature. The other two seg- 1C0 the commutator to turn uponthe collector, whereby the currents induced in the coils are taken off by the collector-segments and thence conveyed ofi by suitable conductors leading from the collector'-segments.- Thisis the gen- 5 eral planof the construction which I have in vented; Aside from certain adjuncts, the nature and functions of which will be hereinaf ter set forth, this means of commutatiouwill be scen'to possess many important advan 6c tages. In the first place" the 'short-circuiting and breaking of the armature-coil connected to the commutator-segments occur at the same instant, and from the nature of a the construc tion this will be done with the greatest preci'sion; secondly, the duration of both the break and that of the short circuit will be reduced to a minimum. The first results in a reduction which amounts practically to a suppression of the spark, since the break and the short circuit produce opposite effects in the armature-coil. The second has the effect of, diminishing the destructive eil'ect of a spark, since this would be in a measure proportioned to the durationof thesparlqwhile lessening the duration of the short circuit obviously .increases the elficiency'of' the machine.. The mechanical advantages'will be better understoodby-referriug to the accompanying drawings, in which-- 8c Figure 1-isa central longitudinal section of r the end of a shaft with my improved commut'ator carried thereon. Fig. 2 is a view of the inner or hearing face of the collector. Fig. 3 is an end viewfrom the armature side of a modified form'of commutator. i FigsA and 5 are views of detailsof Fig. 3. Fig. 6 is a loug'itudinal central sectionof another modification, and Fig. 7 iso. sectional view of the same. I A is the end of the armature-shaft of a dynaino-electric machine or motor.

A is a sleeve of insulating material around the shaft, secured in place hy a' screw, a, -'or by other suitable means.

The commutator proper is in the form of a 5 disk which is-made up of four segments,.D I) GG', similar-to those shown .ilL'Eig. 3. Two

as D D, are of metal and practically the same width or extent as the justcd'and set to the desired position.

' I prefer in the form shown in Figs. 1 and 2 parts.

lector are made in substantially the same maninsnla ting segments or spaces of the commutator. The collector" is secured to a-sleeve, B, by screws g g, and the sleeve is arranged to turn freely on the shaft A. The end of the sleeve B is closed by a plate, as f, upon which presses a pivot-pointed screw, h, adj ustable in a spring, H, which acts to maintain the collector in close contact with the commutator and to compensate for the play of the shaft. Any convenient means is employed to hold the collector so thatjt may not turn with the shaft. For example, Ishave shown a slotted plate, K, which is designed to be attached to a stationary support, and an arm extending from the collector and carrying a clamping screw, L, by which the collector may be adto lit the insulatingrsegments of both commututor and collector loosely and to provide some means-as, for example, light springs e e, secured to the bands A B, respectively, and bearing against the segments-to exert alight pressure upon them and keep them in close contact and to compensate for wear, The metal segments of the commutator may be moved forward by loosening the screw a.

The circuit or line wiresare led'from' the metal segments of the collector, being secured.

thereto in any convenient manner','the'plan of connections being shown as applied to a modified form of the commutator in Fig. 6. 'The commutator and the collector in thus presenting two flat and smooth bearing-surfaces prevent-by mechanical action the occurrence of 'hard material capable of being polished and formed with sharp edges. Such materials as glass, marble, or soapstone may be advanta geonsly used. The metal segments are preferably of-copper or brass; butthey may have a facing or edge of durable material--such as platinum or the like-where the sparks are liable tooccur.

I n Fig. 3 a somewhat modified form of my invention is shown, a form designed to facilitate the construction and replacing of the In this form the commutator and colner as previously described, except that the,

ments of each part, however, are secured to their respective sleeves by screws 9 g, and one edge of each se ment is cut away,'so that small plates a b may he slipped into the spaces thus'formed. OF these plates a a are of metal, and are in contact with the metal segments D Di, respectively. The other two, ()1), are of glass 0r marble, and they are all preferably square, as shown in Figs. 4 ends, so that they may be turned to present new edges should any edge become worn by use. Light springs d bear upon these plates and press'those in the commutator toward thosc'in the collector, and insulating-strips c c are secured to 'thc periphcry of the disks to prevent the blocl-zsfroin being thrown out by-centrifugal action. These plates are, of course, useful at those edges of the segments only where sparks are liable to occur, and, as they are easily replaced, they are of great advantage. with platinum or silver. I

In Figs. 6 and 7 is shown the construction which I use when, instead of solid segments, a fluid is employed. In this case the commutator and collector are made of two insulating-disks,

S T, and in lieu of the metal segments a space is cut out of each part, as at R R, corresponding in shape and size to a metal segment.

bands B C may be omitted. The four seg- I prefer to coat them The two parts are fitted smoothly and the collector T heldby the screw h and spring H against the commutator S. 4 As in the other cases, the commutator revolves while the collector remains stationary. The ends of the coils are connected to binding-posts s s, wh1ch are in electrical connection with metal plates t t within the recesscs'iu the two parts S T. These chambers or recesses are filled with mercury, and in the collector part are tubes W W, with screws w 10, carrying springs X and pistons X, which compensate for the ex pension and contraction of the mercury under varying temperatures, but which are sufficiently strong not to yield to the pressure of the fluid'dne, Le centrifugal action, and which serve as binding-posts. 1

In all the above cases I have described commutators adapted for a single coil,and the device is particularly adapted to such purposes.

The number of segments may be increased,

however, or more than one commutator used illustration of the invention, what I claim as new is- 1. In a dynamo-electric machine, the combinatiomwith a commutator formed with condncting terminals or segments with interven ing insulating-spaces, of a collector adapted.

to bear upon the surface of thecommntatoh and formed with conducting terminals or segments equal in extent to the insulating-space between the commutator-segments, as set forth. 2. lfhe combination, with a commutator 5 built or formed of alternate blocks or seg ments of conducting and insulating material, of a collector adapted to bear upon the surface of the commutator and formed of conducting blocks or segments of a width or egtent equal 10 to that of the insulating-segments of thecom mutator and separated by interposed blocks or segments of insulating material, as described.

3. The combination, with a commutator x 5 formed as a disk with alternate terminals or segments of conducting and insulating material, of a collector similarly formed and mounted with its face in contact with that of the commutator, as set forth.

2o 4. The combinationmith acommutator haviing spring-pressure to force the two bearing- 2 5 surfaces together, as set forth.

5. The combination,'witha commutator and a collector the bearing-surfaces of which are identical in respect to the disposition of the conducting and insulating parts, of means for 0 applying springpressure to maintain the two bearing-surfaces in contact and means for holding the collector against rotary movement, as

set forth.

--Signed this 21st day of April, 1887.

NIKOLA TESLA.

Witnesses:

Ron'r. F. GAYLOBD, FRANK E. HARTLEY. 

